Altec 9940a poweramp si

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Page 1

QUTION:

IMPORTANT:

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FRONT PANEL CONTROLS AND FEATURES

1 VU meters

Display output for channels 1 and 2. Meters illumi-
nate when power is on.

2 VOLUME controls

Adjust gain of channels 1 and 2. Rotate clockwise
to increase gain.

3 METER RANGE
switches

Select lull scale range of VU meter. Selectable
ranges are 0 dB, -10 dB and -20 (18. Maximum
output ol each range (0 dB. _ 10 dB and -20 dB)
coincides with zero dB on meter scale.

4 POWER switch

Applies primary power to amplilier. VU meters
illuminate when switch is turned to ON,

5 POWER OUTPUT switch

ln DUAL position, channel 1 and channel 2 inputs
are amplilied and applied to CH 1 and CH 2 OUT
jacks. tor separate sound reproduction of each
channel. in MONO position. channels are bridged
at BAL MONO OUT jacks tor BOO-watt Iloating
capabilityx or dual 200watt capability through indi-
vidual outputs; signal is provided from channel 1
input, Channel 2 input is removed durlng MONO
operation.

When fan accessories are not used, and amplifier
is used tor continuous servxce under heavy load.
turn switch to 40% position to prevent amplifier
from cycling due to excessive heat. In all other
applications, use 100% position lor lull power
output.

SOUND PRODUCTS DIVISION

1515 5. Manchester Ave., Anaheim, Calif. 92803

9440A POWER AMPLIFIER

Reg. u.s Patent No, 1987.342

OPERATING
INSTRUCTIONS

INSTALLATION
RACK MOUNTING

The 9440A amplilier is designed lor mount»
ing in a standard 19-inch equipment rack.
requiring a vertical rack space of 7 Inches.
Use four 10-32 x V2" screws to secure the
front panel against the rack.

VENTILATION

The 9440A must be adequately ventilated to
prevent excessive temperature rise of out-
put transistors. An inch or two at space
should he tell behlnd, above and below the
9440A to ensure adequate cooling. Four
teet raise the amplifier from a flat suriace
to allow tree passage ol air beneath the
chassis.

CAUTION

Do not block ventilation slots in the
top of the chassis. the bottom of the
chassis, or the heat sink shroud at the
back ol the amplifier. Be sure tree cir-
culation ol alr Is not restricted by
other equipment, walls. curtains or
lurniture.

The 9440A should not be placed too close
to other heal-generating equipment or in
areas where ambient temperature exceeds
55°C (131°F).

If the 9440A is mounted in an equipment
rack or cabinet with other heat-producing
equipment mounted above and/or below.
space must be provided between the units
to prevent excessive temperature rise. The
ALTEC 10399 13/4" Parlorated Panel is
recommended for this purpose.

When several ampliliers or other heat~
producing units are installed in a single
rack or cabinet, acceptable air temperature
may be in doubt. To determine temperature
conditions, operate the system until temp-
erature stabilizes. then measure air temper-
ature with a bulb-type thermometer held at
the bottom ol the uppermost amplifier. Do
nnt let the thermometer bulb touch metal
because the metal may be hotter than the
ambient air. ll air temperature exceeds
55°C (131"F). the equipment should be
spaced farther apart or a blower should be
installed to ventilate the cabinet.

Speciﬁcaliollx and componenlt' sublecl to change without
notice. Overall performance will be rtrlzinrairted or improved.

1977. AIIEC Corporation

4202704475508
LITHO lN U.S.A.179-IK

Page 2

REAR PANEL CONNECTIONS AND FEATURES

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Fuse

Protects amplifier from excessive current drain.
Replace only with same type 10»ampere fuse. Refer
to qualitied service personnel it fuse blows re-
peatedly. A iii-ampere fuse may be used lor test
purposes only.

SWITCHED AC

Provrcle auxiliary line voltage. turned on by POWER

OUTLETS switch on front panel. Total current trom both
outlets limited to 1.5A by internal fuse.

CH 1 OUT Connect channel 1 and channel 2 speakers for

CH 2 OUT corresponding channels. Two pair ol standard GR

speaker terminals

jacks have red (+) and black (-) polarity designa»
lions. When two or more speakers are connected
in parallel. combined impedance should be not less
than 4 ohms.

BAL MONO OUT
speaker terminals

Connect balanced output to speaker system. NEVER
CONNECT EITHER TERMINAL TO GROUND. When
two or more speakers are connected in parallel.
combined impedance should be not less than 8
ohms. Operate POWER OUTPUT switch in MONO
mode.

TO ADD AMP jacks

Accept cables to connect another 9440A amplifier
in paralleil

UNBAL INPUT jacks

Accept cables from highlmpedance (nominal 15KQ)
microphones, AMIFM tuners. tape recorders. etc.

BAL HIGH 2 lNPUTS
receptacles

Accept cables lrorn high-Impedance lnorninal 15KQ)
microphones, AMIFM tuners. tape recorders. etc.
Two transformer-isolated. balanced input channels
have XLR3»31 type connectors.

if the 9440A amplifier becomes too warm.
due to continuous use at high output. two
accessory fans should be installed on the
rear of the heat sink shroud. Each tan
should produce at least 30 cubic feet per
minute at a static pressure of 004 inch of
water. Fans provided In the ALTEC Model
105878 Fan Kit meet this requirement.

ELECTRICAL
120-Volt. 50/60 Hz Power Connections

Equipment supplied for domestic use is
provided with the power transformer pri-
mary strapped for 120 volts. as shown in
Figure 1. The power input nameplate,
adjacent to the power cord on the chassis,
is mounted to show the appropriate side
specllying connections. Verify that line
voltage is in accordance with the voltage
rating before connecting primary power.

240-Volt. 50/50 Hz Power Connections

Export equipment is provided with the
power lianslormer primary strapped for

240 volts, as shown in Figure 1. The
power input nameplate. adjacent to the
power cord on the chassis. is mounted to
show the appropriate side specitylng
connections.

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For 3 9440A previously wired for 120 volts
at: primary power. use the following pro-
cedure to change wiring tor 240 volts ac
operation. Refer line voltage change to
qualified service personnel only.

Step 1. Turn POWER switch to OFF.

Step 2. Remove power cord irom primary
power outlet.

Step 3, Remove seven screws securing
top cover. Lllt all top cover to
expose transformer terminal
board.

Step 4. Locate strap connecting terminals
C and F (see Figure 1). Remove
strap and store for possible later
use.

Step 5. Locate strap connecting terminals
E and K. Remove spade connector
from terminal K and connect it to
terminal F. This strap now con-
nects terminals E and F as shown
in Figure 1.

Step 6. install top cover on amplifier and
secure with seven screws removed
in Step 3.

Step 7. Remove voltage rating plate from
chassis; reverse and reinstall to
show 240-volt rating.

NOTE
Switched ac outlets provide 120V ac
when amplilier is strapped for 240V ac

operation. Maximum acceptable
power drain remains 150 watts
combined.

input Connections - Unbalanced

Connections to UNBAL INPUT for channels
1 and 2 are made with twoewire cables
terminated with standard W" diameter
phone plugst

The UNBAL INPUT connects preamplifiers.
mixers. etc., to channels 1 and 2 (see Fig-
ure 2). Nominal input level should be
approximately 0.5 volt rms. If the 9440A Is
used in a mono mode. use the channel 1
(CH 1) lack only; connection of an input to
channel 2 (CH 2). with no connection to
channel 1, will result in no output.

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Figure 1. Strapping of Power Transformer for 120V and 240V Power